Fungicidal active substance combinations

ABSTRACT

The present invention relates to a novel fungicidally active compound combination comprising 2-[α-{[(α-methyl-3-trifluoromethylbenzyl)imino]oxy}-o-tolyl]glyoxylic acid methyl ester O-methyl oxime of the formula (I)  
                 
the active compound of the formula (II) mentioned in the disclosure.

The present invention relates to a novel active compound combinationwhich comprises, on the one hand, the known2-[α-{[(α-methyl-3-trifluoromethyl-benzyl)imino]oxy}-o-tolyl]glyoxylicacid methyl ester O-methyl oxime and, on the other hand, a knowntriazole derivative and is highly suitable for controllingphytopathogenic fungi.

It is already known that2-[α-{[(α-methyl-3-trifluoromethylbenzyl)imino]oxy}-o-tolyl]glyoxylicacid methyl ester O-methyl oxime has fugicidal properties (cf. EP-A-460575). The activity of this substance is good; however, at lowapplication rates it is sometimes unsatisfactory.

Furthermore, it is already known that numerous azole derivatives can beused for controlling fungi (cf. Pesticide Manual, 11^(th) Edition(1997), page 1144). However, the activity of these compounds, too, isnot always satisfactory at low application rates.

It has now been found that the novel active compound combinationcomprising

2-[α-{[(α-methyl-3-trifluoromethylbenzyl)imino]oxy}-o-tolyl]glyoxylicacid methyl ester O-methyl oxime of the formula (I)

and

the compound of the formula (II)

has very good fungicidal properties.

Surprisingly, the fungicidal action of the active compound combinationaccording to the invention is considerably higher than the sum of theactions of the individual active compounds. Thus, an unforeseeable truesynergistic effect is present, and not just an addition of activities.

The component present in the active compound combination according tothe invention in addition to the active compound of the formula (I) islikewise known. Specifically, the active compounds are described in thefollowing publications:

Compound of the formula (I): EP-A-460 575

Compound of the formula (II): WO 96/16048.

If the active compounds in the active compound combination according tothe invention are present in certain weight ratios, the synergisticeffect is particularly pronounced. However, the weight ratios of theactive compounds in the active compound combination can be varied withina relatively wide range.

In general,

0.02-20 parts by weight, preferably 0.05-10 parts by weight, of activecompound of the formula (II)

are present per part by weight of active compound of the formula (I).

The active compound combination according to the invention has very goodfungicidal properties and can be employed for controllingphytopathogenic fungi, such as Plasmodiophoromycetes, Oomycetes,Chytridiomycetes, Zygomycetes, Ascomycetes, Basidiomycetes,Deuteromycetes, etc.

The active compound combination according to the invention isparticularly suitable for controlling cereal diseases, such as Erysiphe,Cochliobolus, Pyrenophora, Rhynchosporium, Septoria, Fusarium,Pseudocercosporella and Leptosphaeria and for controlling fungalinfections of non-cereal crops such as vine, fruits, groundnuts,vegetables, for example Phythophthora, Plasmopara, Pythium, and powderymildew fungi, such as, for example, Sphaerotheca or Uncinula, andcausative organisms of leaf spot, such as Venturia, Alternaria andSeptoria, and also Rhizoctonia, Botrytis, Sclerotinia and Sclerotium.

The fact that the active compound combination is well tolerated byplants at the concentrations required for controlling plant diseasespermits the treatment of above-ground parts of plants, of propagationstock and seeds, and of the soil. The active compound combinationaccording to the invention can be employed for foliar application orelse as seed dressing.

The active compound combination according to the invention may also beemployed to increase the harvest yield. Moreover, it has reducedtoxicity and is tolerated well by plants.

According to the invention, it is possible to treat all plants and partsof plants. Plants are to be understood here as meaning all plants andplant populations such as desired and undesired wild plants or cropplants (including naturally occurring crop plants). Crop plants can beplants which can be obtained by conventional breeding and optimizationmethods or by biotechnological and genetic engineering methods orcombinations of these methods, including the transgenic plants andincluding the plant cultivars which can or cannot be protected by plantbreeders' certificates. Parts of plants are to be understood as meaningall above-ground and below-ground parts and organs of plants, such asshoot, leaf, flower and root, examples which may be mentioned beingleaves, needles, stems, trunks, flowers, fruit-bodies, fruits and seedsand also roots, tubers and rhizomes. Parts of plants also includeharvested plants and vegetative and generative propagation material, forexample seedlings, tubers, rhizomes, cuttings and seeds.

The treatment of the plants and parts of plants according to theinvention with the active compounds is carried out directly or by actionon their environment, habitat or storage area according to customarytreatment methods, for example by dipping, spraying, evaporating,atomizing, broadcasting, brushing-on and, in the case of propagationmaterial, in particular in the case of seeds, furthermore by one ormulti-layer coating.

The active compound combination according to the invention can beconverted to the customary formulations, such as solutions, emulsions,suspensions, powders, foams, pastes, granules, aerosols andmicroencapsulations in polymeric substances and in coating compositionsfor seeds, and ULV formulations.

These formulations are produced in a known manner, for example by mixingthe active compounds or active compound combinations with extenders,that is liquid solvents, liquefied gases under pressure and/or solidcarriers, optionally with the use of surfactants, that is emulsifiersand/or dispersants and/or foam formers. If the extender used is water,it is also possible to use, for example, organic solvents as auxiliarysolvents. Essentially, suitable liquid solvents include: aromatics suchas xylene, toluene or alkylnaphthalenes, chlorinated aromatics orchlorinated aliphatic hydrocarbons such as chlorobenzenes,chloroethylenes or methylene chloride, aliphatic hydrocarbons such ascyclohexane or paraffins, for example petroleum fractions, alcohols suchas butanol or glycol and their ethers and esters, ketones such asacetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone,strongly polar solvents such as dimethylformamide and dimethylsulphoxide, or else water. Liquefied gaseous extenders or carriers areto be understood as meaning liquids which are gaseous at ambienttemperature and under atmospheric pressure, for example aerosolpropellants such as butane, propane, nitrogen and carbon dioxide.Suitable solid carriers are: for example ground natural minerals such askaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite ordiatomaceous earth, and ground synthetic minerals such as finely dividedsilica, alumina and silicates. Suitable solid carriers for granules are:for example crushed and fractionated natural rocks such as calcite,marble, pumice, sepiolite and dolomite, or else synthetic granules ofinorganic and organic meals, and granules of organic material such assawdust, coconut shells, maize cobs and tobacco stalks. Suitableemulsifiers and/or foam formers are: for example nonionic and anionicemulsifiers, such as polyoxyethylene fatty acid esters, polyoxyethylenefatty alcohol ethers, for example alkylaryl polyglycol ethers,alkylsulphonates, alkyl sulphates, arylsulphonates, or else proteinhydrolysates. Suitable dispersants are: for example lignin-sulphitewaste liquors and methylcellulose.

Tackifiers such as carboxymethylcellulose and natural and syntheticpolymers in the form of powders, granules or latices, such as gumarabic, polyvinyl alcohol and polyvinyl acetate, or else naturalphospholipids such as cephalins and lecithins and syntheticphospholipids can be used in the formulations. Other additives can bemineral and vegetable oils.

It is possible to use colorants such as inorganic pigments, for exampleiron oxide, titanium oxide and Prussian Blue, and organic dyestuffs suchas alizarin dyestuffs, azo dyestuffs and metal phthalocyanine dyestuffs,and trace nutrients such as salts of iron, manganese, boron, copper,cobalt, molybdenum and zinc.

The formulations generally comprise between 0.1 and 95% by weight ofactive compounds, preferably between 0.5 and 90%.

The active compound combination according to the invention, as such orin its formulations, can also be used in a mixture with knownfungicides, bactericides, acaricides, nematicides or insecticides, tobroaden the activity spectrum or to prevent the development ofresistance, for example. In many cases, synergistic effects are obtainedhere, i.e. the activity of the mixture is greater than the activity ofthe individual components.

A mixture with other known active compounds such as herbicides or withfertilizers and growth regulators is also possible.

The active compound combinations can be used as such, in the form oftheir formulations or as the use forms prepared therefrom, such asready-to-use solutions, emulsifiable concentrates, emulsions,suspensions, wettable powders, soluble powders and granules. They areused in the customary manner, for example by watering, spraying,atomizing, scattering, spreading, and as a powder for dry seedtreatment, a solution for seed treatment, a water-soluble powder forseed treatment, a water-soluble powder for slurry treatment, or byencrusting.

When using the active compound combination according to the invention,the application rates can be varied within a relatively wide range,depending on the kind of application. In the treatment of parts ofplants, the application rates of active compound combination aregenerally between 0.1 and 10 000 g/ha, preferably between 10 and 1 000g/ha. In the treatment of seeds, the application rates of activecompound combination are generally between 0.001 and 50 g per kilogramof seed, preferably between 0.01 and 10 g per kilogram of seed. In thetreatment of the soil, the application rates of active compoundcombination are generally between 0.1 and 10 000 g/ha, preferablybetween 1 and 5 000 g/ha.

In fungicides, a synergistic effect is always present when thefungicidal activity of the active compound combinations exceeds thetotal of the activities of the active compounds when appliedindividually.

The expected activity for a given combination of active compounds can becalculated according to S. R. Colby (“Calculating Synergistic andAntagonistic Responses of Herbicide Combinations”, Weeds 1967, 15,20-22) as follows:

If

-   -   X is the efficacy when applying active compound A at an        application rate of m g/ha,    -   Y is the efficacy when applying active compound B at an        application rate of n g/ha and    -   E₁ is the efficacy when applying the active compounds A and B at        application rates of m and n g/ha, respectively,

then ${E1} = {X + {Y\frac{X \cdot Y}{100}}}$

The efficacy is calculated in %. 0% is an efficacy which corresponds tothat of the control, whereas an efficacy of 100% means that no infectionis observed.

If the actual fungicidal activity exceeds the calculated value, then theactivity of the combination is superadditive, i.e. a synergistic effectexists. In this case, the efficacy which was actually observed must begreater than the value for the expected efficacy E₁ calculated from theabovementioned formula.

EXAMPLE A

Leptosphaeria nodorum test (wheat)/protective

Solvent: 25 parts by weight of N,N-dimethylacetamide

Emulsifier: 0.6 part by weight of alkylaryl polyglycol ether

To produce a suitable preparation of active compound, 1 part by weightof active compound combination is mixed with the stated amounts ofsolvent and emulsifier, and the concentrate is diluted with water to thedesired concentration.

To test for protective activity, young plants are sprayed with thepreparation of active compound at the stated application rate. After thespray coating has dried on, the plants are sprayed with a sporesuspension of Leptosphaeria nodorum. The plants remain in an incubationcabin at 20° C. and 100% relative atmospheric humidity for 48 hours.

The plants are placed in a greenhouse at a temperature of about 15° C.and a relative atmospheric humidity of 80%.

Evaluation is carried out 10 days after the inoculation. 0% means anefficacy which corresponds to that of the control, whereas an efficacyof 100% means that no infection is observed. TABLE A Leptosphaerianodorum test (wheat)/protective Application rate of active Activecompound compound in g/ha Efficacy in % Known: Ex. (I) 100 67 Ex. (II)100 56 Mixture according to the invention: Ex. (I) + Ex. (II) 54 + 46 89(10:8.5)

EXAMPLE B

Puccinia test (wheat)/curative

Solvent: 25 parts by weight of N,N-dimethylacetamide

Emulsifier: 0.6 part by weight of alkylaryi polyglycol ether

To produce a suitable preparation of active compound, 1 part by weightof active compound combination is mixed with the stated amounts ofsolvent and emulsifier, and the concentrate is diluted with water to thedesired concentration.

To test for curative activity, young plants are inoculated with a sporesuspension of Puccinia recondita in a 0.1% strength aqueous agarsolution. 48 hours after the inoculation, the plants are sprayed withthe preparation of active compound at the stated application rate.

The plants are placed in a greenhouse at a temperature of about 20° C.and a relative atmospheric humidity of about 80% to promote thedevelopment of rust pustules.

Evaluation is carried out 10 days after the inoculation. 0% means anefficacy which corresponds to that of the control, whereas an efficacyof 100% means that no infection is observed. TABLE B Puccinia test(wheat)/curative Application rate of active Active compound compound ing/ha Efficacy in % Known: Ex. (I) 25 0 Ex. (II) 25 43 Mixture accordingto the invention: Ex. (I) + Ex. (II) 8.5 + 16.5 71 (1:2)

1-5. (canceled)
 6. An active compound combination comprising a compoundof formula (I)

a compound of formula (II)


7. An active compound combination according to claim 6 in which theweight ratio of the compound of formula (I) to the compound of formula(II) is from 1:0.02 to 1:20.
 8. A method for controlling fungicomprising applying an effective amount of an active compoundcombination according to claim 6 to the fungi and/or their habitat.
 9. Aprocess for preparing a fungicidal composition comprising mixing anactive compound combination according to claim 6 with one or moreextenders and/or surfactants.